Without stating as a technical argument with premises and so on, the basic thrust is this:
The world around us is plainly contingent: The realities we experience (yourself, your dog, today’s thunder storm, that water molecule, etc.) do not exist in themselves. Instead, they depend on other realities–whether they be internal combinations and parts or outside factors. My cat doesn’t have to exist, nor do I.
But can every reality in existence be like this? Can every reality be merely contingent and dependent on something outside itself?
NO! If that were the case, if all realities in existence were contingent, then ultimately nothing could be explained. Every reality would be awaiting its existence. In order for you to exist right now, you can not only be dependent on things receiving existence.
Rather, there must be at least one reality who has existence of its very nature. If not, then nothing could receive existence or being.
What is the nature of reality that is NOT contingent?
It can not have physical restrictions: localized here, or acting in this particular manner (like a proton rather than an electron). If that were the case, then its own existence would be dependent on some principle outside itself – some reality that accounts for the manner of this alleged non-contingent reality’s manner of existence. That would make it contingent and NOT the ultimate reality.
So, ultimately, the ultimate reality that is NOT contingent can not be restricted by something outside of itself.
That there is enough to suggest that ultimate reality (1) can not be more than one and (2) can not be physical – not matter, not localized, not conditioned by time and space.
